A Novel Lipid-Based MALDI-TOF Assay for the Rapid Detection of Colistin-Resistant Enterobacter Species

Smith RD, McElheny CL, Izac JR, Gardner FM, Chandler CE, Goodlett DR, Doi Y, Johnson JK, Ernst RK. Microb Sectrum 2022 Feb 2.

Enterobacter species are classified as high-priority pathogens due to high prevalence of multidrug resistance from persistent antibiotic use. For Enterobacter infections caused by multidrug-resistant isolates, colistin (polymyxin E), a last-resort antibiotic, is a potential treatment option. Treatment with colistin has been shown to lead to emergence of polymyxin resistance. The primary mechanism for colistin resistance is modification of terminal phosphate moieties of lipid A, leading to decreased membrane electronegativity and reducing colistin binding affinity. Detection of these modifications, including the addition of phosphoethanolamine and 4-amino-4-deoxy-l-arabinose (Ara4N), can be used for prediction of colistin resistance using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The objective of this study was to identify lipid A markers for colistin resistance in Enterobacter species and Klebsiella aerogenes (formerly Enterobacter aerogenes). … Continue readingA Novel Lipid-Based MALDI-TOF Assay for the Rapid Detection of Colistin-Resistant Enterobacter Species

Rapid identification of mcr-1-positive Escherichia coli from patient urine using a novel lipid-based MALDI-TOF-MS assay

Smith RD, Izac JR, Ha M, et al. Access Microbio. 2021 Dec 17

Mobilized colistin resistance (mcr) genes confer resistance to colistin, a last-resort antibiotic for multidrug-resistant Gram-negative infections. In this case report, we describe a novel lipid-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) diagnostic used to rapidly identify an mcr-1-positive Escherichia coli directly from a patient with a urinary tract infection without the need for ex vivo growth. … Continue readingRapid identification of mcr-1-positive Escherichia coli from patient urine using a novel lipid-based MALDI-TOF-MS assay